1. Field of the Invention
The present invention relates to thermal transfer printing and more particularly a thermal transfer printer structure including a separate resistive ribbon and transfer ribbon and to a technique for moving the resistive ribbon on the transfer ribbon.
2. Description of the Prior Art
Resistive ribbon thermal transfer printing is a form of electro-thermal printing. Representative prior art references in this technology include U.S. Pat. No. 4,309,117 issued Jan. 5, 1982 to Chang et al entitled RIBBON CONFIGURATION FOR RESISTIVE RIBBON THERMAL TRANSFER PRINTING which describes an apparatus which has an improved ribbon configuration containing a two-ply resistive element positioned on a conductive element.
U.S. Pat. No. 4,329,071 issued May 11, 1982 to Applegate et al entitled CURRENT COLLECTOR FOR RESISTIVE RIBBON PRINTERS describes a printer with a ribbon having a central conducting layer covered on one side by a resistive layer that receives electrical printing currents and on the other side by a thermally transferrable ink layer.
Other references in this technology include the following publications.
IBM Technical Disclosure Bulletin, "Thermal Display Printer", Kitamura, vol. 16, No. 7, December 1973, p. 2189.
IBM Technical Disclosure Bulletin, "Resistive Ribbon Thermal Transfer Printing Method", Crooks et al., vol. 19, No. 11, April 1977, p. 4396.
IBM Technical Disclosure Bulletin, "Resistive Ribbon Printing of Typewriter Keys", Wilbur, vol. 20, No. 12, May 1978, p. 5314.
IBM Technical Disclosure Bulletin, "Integrated Polyacetylene Structure for Resistive Ribbon Thermal Transfer Printing", Clarke et al., vol. 21, No. 12, May 1979, p. 5011.
IBM Technical Disclosure Bulletin, "Resistive Ribbon Ink Layers", Crooks et al., vol. 22, No. 2, July 1979, p. 782.
Features of the present invention are that a resistive ribbon is used to supply heat to a thermal transfer ribbon to cause printing and that the resistive ribbon is moved on the transfer ribbon in the same direction but at a different velocity.
In U.S. Pat. No. 3,079,604 issued Feb. 26, 1963 to Schwarzer and entitled RECORDING SYSTEM an ink recorder for registering oscillations on a paper is described wherein the strip of paper which is the medium for the recording, is drawn by means of a conventional drive arrangement in a sharp angle across a knife edge. A strip having a layer of coloring matter, for example ordinary carbon paper, such as is used for making copies on a typewriter, serves as a medium for marking the recording medium and is also passed across the knife edge under the recording strip and preferably in the opposite direction, but in a nearly stretched condition, so that it slides past the recording strip while being slightly pressed against it. This is not a resistive ribbon thermal transfer printer system.
In U.S. Pat. No. 3,878,782 issued Apr. 22, 1975 to Coffelt and entitled IMPRINTING MACHINE AND METHOD OF OPERATION, a structure and process is described wherein work members, such as cartons or labels, or the like, which are to be printed are fed through the machine with the machine having a rotary printing head, preferably heated, and a transfer or printing ribbon disposed between the printing head and the workpiece. The printing head rotates continuously and is moved to and from imprinting position by a fluid cylinder. The advancing of the ribbon is synchronized with rotation of the head and takes place only when the printing head moves to printing position, thus conserving the ribbon and causing ribbon advance only when necessary. This is not a resistive ribbon thermal transfer printer system.
In U.S. Pat. No. 4,063,500 issued Dec. 20, 1977 to Abe and entitled ROTARY HOT-STAMPING APPARATUS, a system is described for imprinting characters on a continuous strip of plastics or other material by pressing heated type against a printing ribbon thereon, the strip is fed at constant speed over a platen in a direction opposite to the direction of travel of the printing ribbon from payoff reel to takeup reel. The type is mounted on a rotary type carrier over the platen for revolution in a direction in conformity with the traveling direction of the strip. While the heated type is being pressed against the superposed ribbon and strip over the platen, the ribbon is thereby transported a predetermined distance toward the payoff reel with the strip relative to the platen and, when subsequently released by the type, is pulled back the same distance toward the takeup reel by a spring-energized pullback lever. This also is not a resistive ribbon thermal transfer printer structure.
The prior art does not show a resistive ribbon thermal transfer recording system employing a separate resistive ribbon and separate thermal transfer ribbon wherein a printhead is moving at a first velocity relative to the paper and the resistive ribbon is moving at a different velocity in the same direction to cause the resistive ribbon to skid on the separate transfer ribbon to effect pattern compression printing.